Classifications

• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
  • C01F17/00—Compounds of rare earth metals
  • C01F17/20—Compounds containing only rare earth metals as the metal element
  • C01F17/253—Halides
  • C01F17/271—Chlorides
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
  • C01F17/00—Compounds of rare earth metals
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
  • C01F17/00—Compounds of rare earth metals
  • C01F17/30—Compounds containing rare earth metals and at least one element other than a rare earth metal, oxygen or hydrogen, e.g. La4S3Br6
  • C01F17/36—Compounds containing rare earth metals and at least one element other than a rare earth metal, oxygen or hydrogen, e.g. La4S3Br6 halogen being the only anion, e.g. NaYF4

Definitions

• the present invention relates to novel dehydrated, essentially anhydrous mixtures of rare earth halides and alkaline earth or alkali metal halides and to a process for the production thereof.
• This invention more especially relates to admixtures of rare earth halides and alkaline earth or alkali metal halides of the chloride, bromide or iodide type, comprising a very low percentage of water and a very low amount of rare earth oxyhalide values.
• the rare earth halides are typically produced in an aqueous medium, for example by acid digestion of a rare earth oxide in an aqueous medium.
• the halides produced are hydrated halides comprising a number of molecules of water, typically from 3 to 9 per molecule of halide.
• halides such as, for example, chemical or electrochemical reduction processes for the production of metal, e.g., the production of neodymium or of an alloy of neodymium with other metals.
• Dehydrating processes have also been proposed to this art employing a dehydrating agent such as hydrogen halides, ammonium halides, carbon tetrachloride, phosgene or SOCl 2 , as well as the halogens.
• a dehydrating agent such as hydrogen halides, ammonium halides, carbon tetrachloride, phosgene or SOCl 2 , as well as the halogens.
• the processes described especially by Matumble (C.R. accord. Sci., 134, 427 (1902)) and Kleinheksel and Kremers (JACS, 50, 959 (1928)) entail passing a gaseous stream of a dehydrating agent over the hydrated halide.
• these processes do not permit lowering the concentration of water and/or of oxyhalide to low values, especially when the mass of rare earth halides to be dehydrated is large.
• a major object of the present invention is the provision of an improved process for the dehydration of hydrated rare earth halides to produce, on an industrial scale, novel halide admixtures containing low contents both of water and of oxyhalide values and including alkaline earth or alkali metal halides.
• the present invention features novel dehydrated mixtures of rare earth halides and alkaline earth or alkali metal halides, with the exception of the fluorides, comprising at least 10% by weight of alkaline earth or alkali metal halide and a water content ranging from 0.01% to 2.5%, while the rare earth oxychloride content ranges from 0.01% to 4.5%.
• the subject admixtures which contain but minor amounts of water and oxychloride values, are especially useful raw materials in metallurgical processes for the production of rare earth metals, such as the electrolytic processes, or the reduction of rare earth halides by an alkali metal or alkaline earth metal.
• the alkaline earth or alkali metal halide is present in the mixture in a concentration by weight of at least 10%, advantageously greater than 15% and preferably ranging from 15% to 60%.
• the alkaline earth or alkali metal halides can be present either alone or as mixtures with alkali metal or alkaline earth metal halides.
• Exemplary alkaline earth or alkali metal halides include the calcium, barium, magnesium, lithium, sodium and potassium halides.
• the halogen in the alkaline earth or alkali metal halide can either be different from or identical to that of the rare earth halide.
• the preferred alkaline earth halide of the invention is calcium chloride and the preferred alkali metal halide is sodium chloride or potassium chloride.
• rare earths are intended the rare earth elements designated the lanthanides which have atomic numbers ranging from 57 to 71, inclusive, as well as yttrium which has an atomic number of 39.
• ceric rare earths are intended the lightest elements, beginning with lanthanum and extending to samarium in terms of atomic number
• yttric rare earths are intended the heaviest elements of the rare earths, beginning with europium and extending to lutetium, and including yttrium.
• the present invention is applicable to all of the halides of these elements and especially to the halides of lanthanum, neodymium, cerium, praseodymium, yttrium and gadolinium.
• this invention features only hydrated rare earth halides.
• the rare earth fluorides are without the scope of this invention, as they do not contain any water of hydration, as are the rare earth halides obtained by an anhydrous route.
• the present invention also features a process for the preparation of the above novel admixtures by dehydration of hydrated halides.
• This process comprises mixing the hydrated rare earth halide with an alkaline earth or alkali metal halide and raising the temperature of such admixture to a value ranging from 150° C. to 350+ C.
• This dehydration is advantageously carried out under partial pressure, for example under a pressure on the order of 1,300 Pa.
• mixture or simply “mixture” is intended a more or less homogeneous mixture of the two halide powders. This mixture can be produced by any means and the homogeneity of such mixture is not critical according to the present invention.
• the optimum temperatures or temperature ranges for dehydration are different for each rare earth halide and depend particularly on the dehydration temperature at which the last molecule of water of the hydrated halide is driven off.
• the rare earth halides to be dehydrated and the alkaline earth or alkali metal halides have halogen atoms which are of the same nature.
• the rare earth halide a halide previously pre-dried by heating, advantageously under reduced pressure, before being mixed with the alkali metal or alkaline earth metal halide.
• a gaseous flux comprising at least one dehydrating halogenated compound, such as, for example, hydrogen halides, ammonium halides, the halogens, carbon tetrachloride, phosgene or S 2 Cl 2 , over or through the mass of the mixture.
• dehydrating halogenated compound such as, for example, hydrogen halides, ammonium halides, the halogens, carbon tetrachloride, phosgene or S 2 Cl 2
• Hydrated neodymium chloride (6.9 moles of water per mole of NdCl 3 ) was intimately admixed with calcium chloride to provide a mixture containing 70% by weight of neodymium chloride and 30% by weight of CaCl 2 .
• This mixture was then heated under reduced pressure (on the order of 1,300 Pa) at a temperature of 240° C for 3 hours.
• the rise in temperature was 1.3° C./min.
• the resulting mixture contained 1.4% of water and 4.1% of neodymium oxychloride (amounts by weight).
• Example 1 The procedure of Example 1 was repeated, but producing a neodymium chloride/calcium chloride mixture containing 50% of calcium chloride.
• the mixture obtained after heating at 300° C. under a pressure of 1,300 Pa contained 2% of water and 3.3% of neodymium oxychloride.
• Example 1 The procedure of Example 1 was repeated, but using a mixture containing 85% of NdCl 3 and 15% of CaCl 2 .
• the resulting mixture had a water content of 1.3% and an oxychloride content of 4.3%.
• Example 1 The procedure of Example 1 was repeated, but using a mixture containing 70% of NdCl 3 and 30% of potassium chloride.
• the resulting mixture contained 2% of water and 2.7% of neodymium oxychloride.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Geology (AREA)
• Inorganic Chemistry (AREA)
• Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=9383016

Family Applications (1)

Country Status (11)

Cited By (11)

Families Citing this family (4)

Citations (8)

Family Cites Families (5)

• 1989
  • 1989-06-22 FR FR8908316A patent/FR2648802B1/fr not_active Expired - Lifetime
• 1990
  • 1990-05-30 KR KR1019900007889A patent/KR910000532A/ko not_active Withdrawn
  • 1990-06-15 EP EP90401669A patent/EP0407242A1/fr not_active Withdrawn
  • 1990-06-20 NO NO90902734A patent/NO902734L/no unknown
  • 1990-06-20 JP JP2160045A patent/JPH0337115A/ja active Pending
  • 1990-06-21 AU AU57730/90A patent/AU623789B2/en not_active Ceased
  • 1990-06-21 CA CA002019489A patent/CA2019489A1/fr not_active Abandoned
  • 1990-06-21 ZA ZA904811A patent/ZA904811B/xx unknown
  • 1990-06-21 FI FI903156A patent/FI903156A7/fi not_active IP Right Cessation
  • 1990-06-22 BR BR909002961A patent/BR9002961A/pt not_active Application Discontinuation
  • 1990-06-22 US US07/541,939 patent/US5178664A/en not_active Expired - Fee Related

Patent Citations (8)

Non-Patent Citations (11)

Also Published As

Similar Documents

Legal Events